1. Field of the Invention
The present invention relates to a photoelectric sensor having a specialized display.
2. Discussion of the Related Art
Photoelectric sensors are typically used for detecting objects. They compare a measured quantity, such as reflected light, with a threshold value to determine whether the object is present or not.
These sensors have a display that can indicate the value of the measured quantity or simply indicate whether the object is present or not. Some sensors include a display that can show the value of the measured quantity and this display can be switched to also show the threshold value. Before the present invention, it was difficult for the operator to easily compare a selected measured quantity with the threshold value since the threshold value was not displayed when the operator selected the display to show a selected measured quantity. Thus, it was difficult for the operator to easily adjust the threshold value based on the real situation that the photoelectric sensor was experiencing. This situation has caused difficulties for the operator because they were required to switch back and forth between displaying the selected measured value and the threshold value.
An object of the invention is to provide a photoelectric sensor that can simultaneously display multiple parameters related to the sensing conditions.
A further object of the invention is to provide a photoelectric sensor that allows easy adjustment of a threshold value.
In one aspect of the invention, there is provided a photoelectric sensor comprising a sensor unit having a casing, the casing including one surface having a first display and a second display. The first display is structured and arranged to display a threshold value that may be set by an operator of the photoelectric sensor. Further, the second display is structured and arranged to display actual conditions sensed by said photoelectric sensor. The sensor also includes a selection device for selecting different operational values to display on the second display. The selection device includes a mechanism disposed on the casing for changing the different operational values on the second display.
In a second aspect of the invention, there is provided a photoelectric sensor comprising a sensor unit having a casing including one surface that has a first display and a second display. The first display is structured and arranged to display a threshold value that may be set by an operator of the photoelectric sensor and the second display is structured and arranged to display actual conditions sensed by the photoelectric sensor. An adjustment switch is also disposed on the casing. The adjustment switch allows for adjustment of the threshold value shown on the first display while the second display shows at least one of the actual conditions sensed by the photoelectric sensor.
In a third aspect of the invention, there is provided a photoelectric sensor comprising a main body unit and a sensor head unit connected by at least one cable. At least one of the main body unit and the sensor head unit includes a casing including one surface that has a first display and a second display. The first display is structured and arranged to display a property set by an operator of the photoelectric sensor and the second display is structured and arranged to display actual conditions sensed by said photoelectric sensor. A selection device is also provided for selecting different operational values to display on the second display. The selection device can include a mechanism like a mode selection switch disposed on the casing for changing the different operational values shown on the second display. Methods of operating the photoelectric sensor are also disclosed herein.